I've gone down a Torben Holmbäck rabbit hole.  This is one of four Desk Blocks that also includes a Tape Block and two different Pencil Blocks .  I call this a Desk Organizer Block because is appears to have a slot for holding letters and a circular cutout for paper clips etc.  I have only found one picture of it (included here) and it is the third item in the row and difficult to see the details.  All of the blocks have the same external dimensions (70 x 105 x 42 mm).   All of the originals were machined from a block of black anodized aluminum.  

As with the others, I've added a cavity in the base that allows you to add self-adhesive wheel weights to give it some heft.  The cavity is designed to hold these wheel weights (Amazon:  https://a.co/d/1S71y2b) in a 3 high stack of 2x2 weights.  I haven't printed this yet but will post pictures when complete.